The invention relates to the field of chemical lasers and, more particularly, to a water vapor trap and liquid separator for use in a singlet-delta oxygen generator.
The chemical oxygen-iodine laser (COIL) is a high-energy chemically pumped continuous wave (cw) laser which utilizes electronic transitions between different states of atomic iodine. The COIL can produce continuous high power waves and good beam quality due to low pressure operation.
The overall process in the COIL involves the liquid phase generation and flow of electronically excited molecular, singlet-delta oxygen, O.sub.2 (.sup.1 .DELTA.), into the gaseous phase. This is followed by electronic energy transfer to metastable atomic iodine to produce the excited state of atomic iodine.
O.sub.2 (.sup.1 .DELTA.) is produced in the singlet-delta oxygen generator by a chemical reaction between basic hydrogen peroxide (BHP), HO.sub.2.sup.-, and chlorine gas, Cl.sub.2. Resonant energy transfer from O.sub.2 (.sup.1 .DELTA.) produces excited state atomic iodine I(P.sub.1/2) and a population inversion in the gain generator of the COIL: EQU O.sub.2 (.sup.1 .DELTA.)+I(P.sub.3/2).fwdarw.O.sub.2 (.sup.3 .SIGMA.)+I(P.sub.1/2) (1)
The ground state iodine atoms for reaction (1) can be produced by the dissociation of molecular iodine, I.sub.2, introduced into a flow stream of O.sub.2 (.sup.1 .DELTA.) in the gain generator. The transition between the first electronically excited state of atomic iodine and the ground state generates a photon at 1.315 .mu.m: EQU I(P.sub.1/2).fwdarw.I(P.sub.3/2)+h.nu.(1.315 .mu.m) (2)
The flow stream of gaseous .degree. 2(.sup.1 A) produced in the singlet-delta oxygen generator also comprises other gases and liquids which can be detrimental to laser beam quality and power. The gas stream typically comprises water vapor which can particularly adversely affect the laser beam. As the percentage of water vapor increases in the flow stream, the laser power decreases. Above about 10% water vapor, the laser power can be reduced to essentially zero. Accordingly, it is important to reduce the amount of water vapor to achieve satisfactory laser power.
Known cold traps for removing water vapor from gaseous O.sub.2 (.sup.1 .DELTA.) produced in singlet-delta oxygen generators include chilled fins over which the gas stream is passed to condense the water vapor. This approach is less than totally satisfactory. Particularly, the fin configurations can be relatively large and heavy. Accordingly, fins are undesirable for use in airborne applications where space is limited and light weight is important to reduce fuel consumption. In addition, the channels defined by the fins become clogged by the ice formed when the water vapor in the gas stream is chilled. This ice formation reduces gas flow through the fins. The ice can also become entrained in the gas flow into the gain generator and reduce laser power.
It is also important to remove the gas-entrained liquids in the O.sub.2 (.sup.1 .DELTA.) gas stream to prevent the liquids from entering the gain generator.
Thus, there is a need for a vapor trap and liquid separator for use in a singlet-delta oxygen generator that (i) effectively removes water vapor from the O.sub.2 (.sup.1 .DELTA.) gas stream without the problems of ice formation and clogging; and (ii) has reduced size and weight; and (iii) effectively separates liquids from the O.sub.2 (.sup.1 .DELTA.) gas stream.